Back-spacing mechanism.



H. A. FOOTHORAP.

BACK SPACING MECHANISM.

APPLICATION FILED 050.14. 1914.

Patented Oct. 31, 1916.

3 SHEETS-SHEET 1.

H. A. FOOTHORAP.

"BACK SPACING MECHANISM. APPLICAfION HLED DEC. 14.. mg.

1,203,520. Patented Oct. 31,1916.

3 SHEETS-SHE ET 2.

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H. A. FOOTHORAP.

BACK SPACING MECHANISM.

APPUCATION HLED 05014, 1914.

Patented Oct. 31, 1916.

3 SHEETS-SHEET 3.

ww zmr UNITED STATES PATENT OFFICE.

HARRY ARTHUR FOOTHORAP, OF HARRISBURG, PENNSYLVANIA, ASSIGNOR TO I ELLIOTT-FISHER COMPANY, OF HARRISBURG, PENNSYLVANIA, A CORPORATION OF DELAWARE.

BACK-SPACING MECHANISM.

Specification of Letters Patent.

Patented Oct. 31, 916.

Application filed December 14, 1914. Serial No. 877,212.

To all whom it may concern:

Be it known that I, HARRY ARTHUR F OOTIIORAI, a citizen of the United States of America, residing at Harrisburg, in the county of Dauphin and State of Pennsylvania, have invented certain new and useful Improvements in Back-Spacing Mechanisms, of which the following is a specification.

This invention relates to back spacing mechanisms for typewriters, the object being to produce a durable and accurately operating mechanism whereby the carriage will be stepped backward upon the depression of the back space key without danger of over-retraction in the event of the application of more than the necessary force to the key.

In the accompanying drawings :-Figure 1 is a sectional view of a portion of an Elliott-Fisher billing machine equipped with my back spacing mechanism, the parts being shown in normal position. Fig. 1 is an elevation showing certain elements of the back spacing mechanism illustrated in Fig. 1 with the parts in the relative positions they assume when the pawl has been thrown into the back space ratchet and the back spacing movement of the carriage commenced. Fig. 2 is a-similar view with the parts in the positions they assume at the completion of the back spacing operation.

Fig. 3 is a detail sectional view showing the mounting of the back space check dog. Fig. 4 is a plan view of the subject matter of Fig. 1. Fig. 5 is a detail view of the back space check dog. Fig. 6 is a similar view of the pawl carrier. Fig. 7 is a detail View. of the actuator, and Fig. 8 is a similar View of the pawl.

1 indicates the deck of an Elliott-Fisher machine from which are suspended front and rear escapement brackets 2. In these brackets are mounted the carriage feed spindle 3 rotatably supporting the escapement wheel 4, the carriage feed pinion 5 and the back space ratchet 6, all of which are niounted in rigid organization to rotate in unison. Co'acting with the escapement wheel are the holding and spacing dogs 7 and 8 constructed and operated in a manner described in my co-pending application, Serial Number 877,211. Mounted to oscillate on the spindle 3 immediately in advance carrier.

rier in its proper normal position when said carrier is swung back under the impulse of a retracting spring 14. The spring 14 is connected at one end to a fixed part as indicated at 15 and at its opposite end to a dog controlling arm 16 projecting from the pawl carrier at a point diametrically opposite the pawl 10. The arm 16 has an angular end 17 which extends under. theback space check dog 18 and normally supports the same in its retracted position. The check dog 18 is mounted on a member 19 in the form of a spindle passing through a boss 20 on one of the brackets 2 and is normally urged toward its engaging or checking position, that is to say, toward the back space ratchet 6 by a spring 21 located in a recess 22 in the check dog and encircling the spindle with its opposite ends connected to the check dog 18 and boss 20 respectively, as shown in Fig. 3. At its limit of checking movement, the dog 18 is arrested by the contact of its tail 23 with a stop 24. In advance of the pawl carrier 9, a back space actuator 25 is mounted to oscillate on the spindle 3. This actuator is in the form of a bell crank lever, one arm 26 of which is bifurcated to straddle the pin 11 carried by the pawl 10 and the other arm 27 of which is connected by a draw wire 28 to the vertical arm of the bell 'crank lever 29 fulcrumed in a hanger 30 carried by the deck 2. The other arm of the lever 29 is connected to the lower end of a draw Wire 31,

connected to the rear end of a sub-lever 32,

fulcrumed on the post 33 and supported by the deck 2. The opposite or front end of the lever 32 is connected by a push rod 34 to the back space lever 35 fulcrumed on the common fulcrum bar 36 of the machine and frame (not shown) of the machine. There- -iore movement of the carriage in either direction is necessarily accompanied by the travel of the pinion 5 on the rack and by the rotary movement of the eseapement wheel. a and back space ratchet 6, both of which, as heretofore stated, are fixed'to the pinion. Consequently the carriage, which is under tension. in the direction of the arrow, Fig. 2, is controlled by the eseapement dogs 7 and 8 which engage theteeth of the escapement wheel and back spacing of the carriage is efiected by reverse rotation of the back space ratchet G. V I

The operation of the back spacing mechanism is as follows: Normally the back space pawl 10 occupies the retracted or completely disengaged position, as shown in Fig. l, the pin 11 projecting from said dog being located at the bottom of the opening in the pawl carrier 9. The arm 12 of the pawl carrier is held against the stop 13 by the action of the spring Li and the back space check dog 18 is held in disengaged position by the dog controlling arm 17 of the pawl carrier. In this position of the elements of the back spacing mechanism, the free movement of the carriage back and forth is unobstructed thereby since the back space ratchet 6 may rotate freely in either direction without interference from either the pawl 10 or the dog 18. Vhen it is desired to back space the carriage, the line space key 37 is depressed and the levers 35, and 29 are swung to move the back space actuator :25 from the normal position shown in Fig. 1. This movement of the actuator elevates the pin 11 of the pawl 10 and swings the pawl independently of its carrier into engagement with a tooth-of the back space ratchet 6. Continued movement of the key will now cause the actuator 25 to swing the pawl carrier 9 by reason of the engagement of the dog 10 with the back space ratchet. As the carrier rotate the line space ratchet and the dog controlling arm 17 of the carrier will drop away from the check dog 18 which, underthe impulse of gravity aided by the spring 21, will swing toward the ratchet, its movement in this direction being arrested by the engagement of its tail 23 with the fixed stop 24. Q'lhisoperatire position of the dog will be reached before the back space movement has been completed so movement is complete, the back face of one ot the teetli of the ratchet 6 will come squarely against the end face of the dog" which will, with certainty, prevent excessive back space movementof the carriage. Upon the release of the' back spacekey, the parts will return to normal position as shown in Fig. 1, the pawl carrier being retracted to present its arm 12 to the stop 13 and to cause the rlog'eontrolling arm 17 to 'wheel in order is swung, the pawl 10 will' that when the l .for the pawl carrier.

the backward movement of the escapement wheel when the back spacing mechanism is operated will swing back the holding dog of the escapement and allow the same to engage the next tooth of the escapement to again place the escapement wheel and carriage under the control of the cscapement in the new 'or back spaced position' of the carriage. 1

It is thought that from the foregoing, the construction and operation of my back spacing mechanism will be fully comprehended and I reserve the right to effect such modifications of the illustrated structure as may come fairly within the scope of the invention.

What I claim is 1. The combination with a carriage feed spindle and rack, of a carriage feed pinion, a back space ratchet and an escapement wheel. fixed to rotate 'in unison on the spindle, a back space pawl carrier and a back space actuator both swung from thespindle, a pawl mounted'on the carrier to engage the ratchet and having a pin extended through the carrier and into engage:- ment with the actuator and means for swinging the actuator to move the pawl into the ratchet and to thereafter swing the bifurcated end engaging the pin, means for swinging the actuator to first move the pawl into the ratchetand to then rotate the ratchet for back spacing, and a, stop device 3. The combination with a. carriage feed rack and pinion, ofa back space ratchet fixed to the pinion, a pawl carrier having a pawl carrying arm and a check dog controlling arm at opposite sides of its axis, a back space pawl mounted on the pawl carrying arm, a check dog normally supported out of cooperative relation with the ratchet by the dog controlling arm of the pawl carrier, an actuator arranged to swing the pawl into the ratchet and to move the pawl carrier for the purpose of rotating the back space ratchet and withdrawing the dog controlling arm from the dog and means for operating the actuator.

4. The combination with a carriage feed spindle, of a feed pinion, a back space ratchet and an escapement wheel connected to rotate in unison on the spindle, a rack engaging the pinion, a pawl carrier "and an actuator also mounted on the feed spindle and having limited independent oscillatory movement, said pawl carrier comprising a pawl carrying arm, a check dog controlling arm and a stop arm, an adjustable stop coacting with the stop arm, a check dog normally held in inactive position by the dog controlling arm of the pawl carrier, a spring urging the dog toward its engaging position, a stop limiting the movement of the dog, a pawl carrier retracting spring con.- nected to the dog controlling arm and the carrier, a back space pawl pivoted to the pawl carrier and engaged by the actuator and operating means connected to the actuator.

5. A back spacing mechanism including a toothed rotary member, an oscillatory pawl carrier and an oscillatory actuator, all coaxially mounted and a back space pawl carried by the carrier and cooperating with the toothed member, the actuator being operative to move the pawl into and out of engagement with the rotary member to operate the pawl carrier.

6. The combination with a carriage feed spindle and rack, of a carriage feed pinion, a back space ratchet and an escapement wheel fixed to rotate in unison on the spindle, a back space pawl carrier and a back space actuator, a pawl mounted on the carrier to engage the ratchet and having a pin extended into engagement with the actuator and means for swinging the actuator to move the pawl into the ratchet and to thereafter swing the pawl carrier to rotate the ratchet.

7. The combination with a carriage feed spindle and rack, of a feed pinion, back space ratchet and escapement wheel mounted on the splndle, dogs coacting with the escape ment wheel, a pawl carrier mounted on the sp1ndle,a pawl pivoted on the carrier to;

cooperativerelationvwith the ratchet by the dog controlling arm of the pawl carrier, an actuator arranged to swing the. pawl into the ratchet and to move the pawl carrier for the purpose of rotating the back space ratchet and withdrawing the dog controlling arm from the dog and means for operating the actuator.

9. The combination with a feed pinion, a

back space ratchet and an escapcment wheel connected to rotate in unison, a rack engaging the pinion, a pawl carrier and an actuator having limited independent oscillatory movement, said pawl carrier comprising a pawl carrying arm, a check dog controlling arm and a stop arm, an adjustable stop coacting with the stop arm, a check dog normally held in inactive position by the dog controlling arm of the pawl carrier, a spring urging the dog toward its engaging position, a stop limiting the movement of the dog, a pawl carrier retracting spring connected to the dog controlling arm and the carrier, a back space pawl pivoted to the pawl carrier and engaged by the actuator and operating means connected to the actuator.

In testimony whereof I afiix my signature in presence of two witnesses.

HARRY ARTHUR FOOTHORAP. Witnesses:

W. J. Evnnr, EDWlN FLOYD. 

